Kylie Jenner may leave fans feeling exhausted by proxy after sharing that she exercises twice per day to keep in shape.

The 23-year-old billionaire reality star is well known for her penchant for posing in bikinis and showcasing her famous curves.

But it seems keeping in tip top shape really does require a lot of maintenance – with the mum-of-one sharing that she was exercising a second time on Thursday just five hours after her morning workout.

Taking to Instagram Stories earlier in the week, Kyle shared video of herself hitting the treadmill, jogging away as she worked up a sweat in black leggings and white trainers.

Kylie Jenner has been updating fans with her fitness routines

She captioned her video: “2nd workout starting, let's gooooo!”

The clip was posted at midday with the star previously working up a sweat at the earlier time 7am.

Back in March a source close to the star said Kyle was keen to get in shape for the summer.

Kyle shared video from her second workout of the day on social media

They told E!: “Kylie is determined now more than ever to get toned for summer.

“She's fully into fitness and health.

“She wants to maintain her figure and stay toned for summer.”

It is believed the star works out in a home gym at her California mansion under the tutelage of a personal trainer.

However the source continued: “She prefers doing outdoor workouts because it's more distracting and feels nice to be in nature.”

Meanwhile, the star is also said to be kept on her toes by running around after her three-year-old daughter.

The reality star is said to be working out to achieve her goal summer body

The source claimed: “She will go on long walks with Stormi on the trails by her house or go for a hike nearby.

“Kylie has been watching what she eats at home but isn't restricting herself.

“When she goes out with friends, she eats what she wants. She has been super motivated recently and is loving the endorphins.”